This application claims the priority benefit of Taiwan application serial no. 90113307, filed on Jun. 1, 2001.
1. Field of Invention
The present invention relates to a fabrication method for a semiconductor device. More particularly, the present invention relates to a fabrication method for a low dielectric constant (k) dielectric material layer.
2. Description of Related Art
The low dielectric constant (k) material is mostly used as the inter-layer dielectrics (ILD) in the manufacturing of the Ultra-Large Scale Integrated (ULSI) circuit. The application of the low k material greatly reduces the RC delay of the device and thereby increases the effectiveness of the device. Moreover, the thermal stability of the low k material also satisfies the manufacturing requirements. The mechanical strength for this type of organic high molecular weight low k material, however, is insufficient. This type of low k material is, therefore, easily damaged in the chemical mechanical polishing (CMP) process of the subsequent manufacturing of a damascene structure. As a consequence, a silicon-containing inorganic dielectric layer is usually formed on the low k material layer as a polishing stop layer. The silicon-containing inorganic dielectric layer includes silicon nitride or silicon carbide.
The bonding between the low k material layer and the silicon nitride or the silicon carbide type of inorganic material, however, is poor. The polishing stop layer is easily peeled off during chemical mechanical polishing, and the underlying organic low k material layer is therefore not being protected, leading to the problem of particulate formation. Conventionally, a hexamethyldisilazane (HMDS) layer is formed on the low k material layer, followed by forming the silicon containing inorganic dielectric layer. Since the adhesion of the silicon containing inorganic dielectric layer to the HMDS layer is better than to the organic low k material layer, using a HMDS layer improves the bonding between the organic low k material layer and the silicon containing inorganic dielectric layer. However, the adhesion of the HMDS layer to the organic low k material layer is only slightly better than that of the silicon containing inorganic dielectric layer to the organic low k material layer. The bonding between the silicon containing inorganic dielectric layer and the organic low dielectric constant material layer is not being improved significantly.
The present invention provides a fabrication method for a low k material layer, wherein a high molecular weight material layer is formed on a substrate, followed by curing the high molecular weight material layer. A bonding material layer is then formed on the high molecular weight material layer. A major component for the bonding material layer includes an organic silicon compound, wherein the organic silicon compound comprises a silicon-containing moiety and an unsaturated hydrocarbon moiety. The bonding material layer is then cured, allowing the organic silicon-containing compound to cross-link with the high molecular weight material layer. The high molecular weight material layer thereby comprises a silicon rich surface. Additionally, the curing for the above high molecular material layer and for the bonding layer can conduct concurrently.
The present invention provides a fabrication method for the inter-layer dielectrics, wherein the low k material layer manufactured according to the present invention comprises a silicon containing high molecular weight material layer. A silicon nitride or silicon carbide type of silicon containing organic material layer is further formed on the high molecular weight material layer.
According to the fabrication method for a low k material layer and inter-metal dielectrics provided by the present invention, the unsaturated hydrocarbon moiety of the organic silicon compound cross-links within the surface of the underlying high molecular weight material layer. Moreover, the silicon-containing moiety of the organic silicon compound has a high affinity to the overlying silicon-containing inorganic material layer. The bonding between the silicon-containing inorganic material layer and the high molecular weight material layer is thus increased to prevent the peeling off of the silicon-containing inorganic material layer.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.